He spent the bulk of his season at Double-A (he had a one start cameo at Triple-A), where he posted a 2.86 ERA and 1.02 WHIP. While he’s continually shown strong control, with a 2.1 BB/9 over his minor league career (2.5 at Double-A), the other skills leave a bit to be desired. While he has an 8.4 K/9 over his minor league career, he was at 7.9 at Double-A. John Sickels of Minor League Ball highlights those concerns as he said:

“many scouts are skeptical because fastball tops out at 92, along with curve and change that draw average grades”

He also has struggled generating groundballs, with a 0.68 GO/AO at Double-A (0.69 over his minor league career), which could lead to home run issues. While he’s posted some solid numbers in the minors, he’s nothing more than a backend starter for a Major League team.

SS Drew JacksonGrade – C
ETA – 2018

A fifth round selection in 2015, Jackson had ranked #9 on our Mariners Top 10 prospect list. He spent last season at High-A, hitting .258 with 6 HR and 16 SB over 524 AB. That came after hitting .358 with 47 SB over 226 AB in his pro debut (Single-A). He did continue to make enough contact (17.6% strikeout rate), though the profile leaves a lot to be desired. As Rich Wilson of Prospect 361 described him:

“Jackson is a classic slappy hitter. He’s up there to make contact and use his wheels to get on base. There are plenty of examples of that approach working but in general, you like to see all players use their lower half to drive the ball.”

There’s little reason to get excited about his long-term outlook, barring a change in approach.

RHP Aneurys ZabalaGrade – C
ETA – 2020

The reliever has spent the past three seasons pitching at Rookie Ball, showing some strikeout stuff but significantly struggling with his control. In 25.0 innings last season he posted 28 K and an impressive 2.27 GO/AO, though he issued 15 walks. He needs to get that in order, because if he does he can be electric. Just look at what MLB.com had to say:

“Zabala made strides with his heater last summer, sitting at 96-99 mph with an improved downhill plane helped him generate more than twice as many outs on the ground than in the air in the AZL. He complements his fastball with a hard, downer curveball that scouts view as an above-average pitch, and he showed the ability to miss bats with both offerings for the first time in 2016.”